Timer Driver circuit help/ideas

Discussion in 'The Projects Forum' started by hannsg, Jun 19, 2009.

  1. hannsg

    Thread Starter New Member

    Jun 19, 2009
    Hello and sorry its a bit complicated for my first post,
    I am trying to rebuild a controller to drive two air solenoids. They are for turning targets at our local shooting range.

    It will need to drive the face solenoid for about second while timing for a preset but variable amount (2-30s hoping to set with pot).

    When this timer has expired drive the away solenoid for about a second while timing for a variable but preset amount (again 2-30s hoping to adjust with a pot).

    When the second time expires it goes back and starts the first time.

    Robbing ideas from the original system, I was thinking about a monostable multivibrator for the timing (page5 fig 15 of datasheet variable resistors to rx1 and rx2):


    Using a darlington array to drive the solenoids using the notQ outputs from the above timer:


    I was going to use 555 timers but this idea looks much better but I have little expierence of cmos circuits. Is there anything I should look out for or be careful of? other than electrostatic precautions?

    I have 24 volts which is also used to drive the solenoids but dont have the solenoid details just yet.

    I think thats all the details Ive been trying to think of the best way to do this for a while has anyone got a better idea?